Field of the Invention
The present invention relates to an image formation technique, and in particular relates to a technique for transitioning into a state in which a high speed startup is possible in a case where an OFF operation is performed on a power supply switch.
Description of the Related Art
There is a problem in that for image forming apparatuses and information processing apparatuses of recent years, it takes a long time, due to an increase in the number of functions in such apparatuses, before a user is actually able to operate the apparatus from when the user performs an operation (an ON operation) on a power supply switch. For this problem, there is a function referred to as suspend (a suspend mode) that puts the device in a state in which operation of currently executing programs is paused when the user performs an OFF operation on a power supply switch so that it is possible to revert back to the same operational state as the current operational state. Also, there is a function referred to as resume for starting up in an operational state from the point in time immediately preceding termination when the user performs an ON operation on a power supply switch, i.e. reverting to a state immediately preceding the point in time of termination. In other words, by using the functions as described above, a high speed startup becomes possible in an image forming apparatus such as a digital multifunction peripheral, and quickly reverting to the immediately preceding operational state becomes possible (Japanese Patent Laid-Open No. 2007-293806).
In an image forming apparatus equipped with devices such as a scanner, a printer, or the like, an arrangement is provided for forcibly turning off a power supply of a device such as a scanner, a printer, or the like, by an OFF operation on a power supply switch. There are cases in which an error is issued due to the power supply of a device, such as a scanner, a printer, or the like, being turned off forcibly, based on an operational state of a device, such as a scanner, a printer, or the like, when a power supply switch is turned off, and a suspend state is transitioned into. In such a case, normally, by notification between apparatuses of the state of the power supply switch, shutdown processing is executed without transitioning into the suspend state. By a system reset accompanying the shutdown processing, the above described error notification is reset, and thereby the image forming apparatus starts up normally. However, there are cases in which, due to the notification of the power supply switch state between apparatuses being delayed, the suspend state is transitioned into without it being possible to recognize the issued error as a misdetection error. In such a case, the apparatus reverts to the error state upon the next start up.